Conventionally, there has been a braking device for an elevator, which keeps a braking state with a pressing force of a spring, and keeps a releasing state with a magnetic force of a permanent magnet. The braking state is switched to the releasing state by energizing an electromagnet coil with a DC current to generate a strong magnetic field in the same direction as that of the permanent magnet, thereby attracting an armature against the force of the spring. After the attraction is completed, the armature can be kept in an attracted state owing to a magnetic force of the permanent magnet even if the DC current is interrupted. The releasing state is switched to the braking state by energizing the coil with a DC current generating a magnetic force that cancels the magnetic force of the permanent magnet (see Patent Document 1, for example).
Patent Document 1: Japanese Utility Model Application Laid-open No. Sho 57-128